[CAUT] FW: Temperature/Humidity range

[Ron Nossaman]

> I'd say that temp will be fine if it's comfortable for the people in the
> building. IOW, a reasonable small range, which will typically be between 68
> and 75 F. They'll have to maintain that to keep the people happy. (Yes, Ron
> is correct that you might have your pianos happiest at a constant 50
> degrees, but that ain't gonna happen).

Hi Fred,
Well, no, that's not what I meant. My point is that the temperature 
can fluctuate quite a bit (even with the heating thermostat set at 
50° in the old country church, it often gets considerably warmer 
than that as the weather fluctuates), and the pianos keep up fairly 
well. It's the humidity extremes resulting from trying to keep a 
constant temperature, that are the problem causing the major 
seasonal pitch changes. The MC of the wood in the piano is what 
we're trying to control indirectly. For instance, a temperature of 
70°F, with a 42%RH results in an 8%MC in an arbitrary piece of wood 
(piano) stored in those conditions. Keeping the RH% at  42 when the 
temperature drops to 50°F results in only a 8.2%MC in the piano, 
where maintaining 70°F temperature and driving the humidity down to 
fairly mild 35%RH results in a 6.2%MC and a pitch raise. Each degree 
F change at a given RH% results in a bit over 0.01%MC change. Each 
1% change of RH at a stable temperature results in approximately 
0.15%MC change. So, given the choice, I'd not spend too much time 
worrying about temperature control, and try to get control of the 
relative humidity.

Ron N